Education

Types of Capacitor

The variety of capacitors available in the market are many and each type of capacitor has its own unique characteristics and applications. These applications could be as small as in a radio circuit to as large as high voltage circuits. Capacitors are considered to be one of the essential electrical components in an electric circuit. They are produced in a million numbers on a daily basis. 

In this article, we shall learn about the material used in the construction along with their advantages, disadvantages, and applications of these various capacitor types. Also, there are other ways to differentiate between the types of capacitors.

Polar and Non-polar

Whether a capacitor is polarized or not is considered to be one of the main distinguishing factors among the capacitors.

What is Polar Capacitor?

Tantalums and aluminum electrolytics are the most common types of polarized capacitors. These capacitors come with an identification mark on them to indicate the positive and negative terminals. When this capacitor is worked under a reverse bias condition, it results in the breaking down of the capacitor.

What is a Non-Polar Capacitor?

When a capacitor comes with no polarity and can be connected to the circuit in either way, it is known as a non-polar capacitor. For instance, plastic film and ceramic capacitors are non-polarized capacitors.

Variable and Fixed Capacitors

The second distinguishing feature of a capacitor is whether they are fixed or variable.

What are Fixed Capacitors?

The fixed capacitor types are the ones that do not come with any adjustments. The availability of fixed capacitors are huge, and they are categorized based on the dielectric that is used in the construction of the capacitor. Examples of the dielectric used in these are silver mica, ceramic, electrolytic, and metalized plastic film.

What are Variable Capacitors?

The variable capacitor is an adjustable capacitor with either a knob or a screw. These are further classified as the variable and present capacitor. The main applications of variable capacitors are during calibration, setup, etc.

Therefore, polar, non-polar, fixed, and variable capacitors can be said to be the base for differentiating the capacitor types.

Ceramic Capacitors

The following is the list of features displayed by the ceramic capacitors:

  • Ceramic capacitors are also known as the disc capacitors.
  • The material of construction in ceramic capacitors is ceramic and silver.
  • These capacitors show non-linear behavior when there is a change in the capacitance and temperature.
  • The determination of the capacitance of the ceramic capacitors is done by imprinting a 3-digit code.

Electrolytic Capacitors

Here is the list of characteristics of an electrolytic capacitor:

  • Most of the electrolytic capacitors are polarized.
  • Electrolytic capacitors find applications in DC power supply circuits.
  • Aluminum electrolytic capacitors and tantalum electrolytic capacitors are the two forms of electrolytic capacitors.

Silver Mica

The following are the information related to silver mica:

  • The manufacture of silver mica capacitors is done by plating silver on mica film.
  • As the layering increases, the required capacitance is achieved.
  • These find applications where the loss is low and the stability is given the utmost importance.
  • The value of these capacitors is between a few picofarads to 2-3 thousand picofarads.

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